For a sake of searching potential candidate for new multiferroic materials in CuO–SeO₂–CuCl₂ composite, Cu₉O₂(SeO₃)₄Cl₆ single crystal was synthesized using a standard vapor-phase method. Magnetic, electrical, and low-temperature synchrotron X-ray diffraction measurements were performed on Cu₉O₂(SeO₃)₄Cl₆. The DC magnetization measurements showed the antiferromagnetic ordering (AFM) of Cu₉O₂(SeO₃)₄Cl₆ near 16 K (T_N) and T_N is decreased with magnetic fields. In addition, the dielectric anomaly near 267 K (T_E) was observed, while no transition in pyroelectric current and polarization-electric field hysteresis-loop could be detected below T_E. The results support that T_E is related to antiferroelectric ordering. However, temperature dependent high-resolution synchrotron X-ray diffractions of Cu₉O₂(SeO₃)₄Cl₆ reveal a structural distortion near T_E. Thus, the comprehensive studies suggest that Cu₉O₂(SeO₃)₄Cl₆ could be a new type-I multiferroic material.